Method for manufacturing touch device and resin composition thereof

ABSTRACT

Discussed is a method for manufacturing a touch device, the method including forming a protective layer per touch sensor on first and second surfaces of a mother substrate on which two or more touch sensors are formed; dividing the mother substrate into two or more substrates of a touch sensor unit by mechanically cutting or chemically treating the mother substrate; chemically strengthening an edge of each of the divided substrates; and removing the protective layer from at least one divided substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This Application is a Divisional of U.S. application Ser. No.14/502,765, filed on Sep. 30, 2014, which claims priority from and thebenefit under 35 U.S.C. § 119(a) of Korean Patent Application No.10-2013-0167355, filed on Dec. 30, 2013, all of these applications arehereby incorporated by reference for all purposes as if fully set forthherein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a method for manufacturing a touchdevice to input information by touch.

Description of the Related Art

As the weight of a display is light and the size of the display is slim,so a touch device is gradually being introduced in order to replace akeyboard or a mouth which needs the additional weight and space. Suchthe touch device may provide a user interface with the high intuitive interms of capable of recognizing the user's operations at the sameposition as an image displayed on a screen.

Although the touch device provides the user interface with the highintuitive, the productivity is low and the processing costs aregradually increasing so that the touch device may be limited to be usedin the display device.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made to address theabove-mentioned and other problems occurring in the related art, and anobject of the present invention is to provide a touch device, a methodfor manufacturing a touch device and a resin composition used in themethod thereof which can improve productivity and cut down processingcosts.

According to one embodiment, there is provided a touch device including:a substrate whose surface roughness is less than 1.2 nm, a touch sensorformed on a surface of the substrate and a flexible printed circuitboard attached to the substrate.

According to another embodiment, there is provided a resin compositionto prevent damage of a surface of a substrate from an etchant when anedge thereof is strengthened. The resin composition includes a resinmixture of 20-50% by weight which includes a phenol resin and a epoxyacrylate resin with a weight ratio of 10:90 to 90:10, and a solvent.

According to another embodiment, a method for manufacturing a touchdevice, includes forming a protective layer per a touch sensor on afirst and a second surfaces of a mother substrate on which two or moretouch sensors are formed, dividing the mother substrate into two or moresubstrates of the touch sensor unit by mechanically cutting orchemically treating the mother substrate, chemically strengthening anedge of each of the substrates and removing the protective layer fromthe substrate.

Accordingly, according to various embodiments, it is possible to improveproductivity and cut down processing costs associated with touchdevices.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a sectional view of a touch device according to oneembodiment of the present invention;

FIG. 2 illustrates a flowchart of a method for manufacturing the touchdevice according to an embodiment of the present invention; and

FIGS. 3 to 7 illustrate processes of a method for manufacturing thetouch device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention will bedescribed with reference to the accompanying drawings. In the followingdescription, the same elements will be designated by the same referencenumerals although they are shown in different drawings. Further, in thefollowing description of the present invention, a detailed descriptionof known functions and configurations incorporated herein will beomitted when it may make the subject matter of the present inventionrather unclear.

In addition, terms, such as first, second, A, B, (a), (b) or the likemay be used herein when describing components of the present invention.Each of these terminologies is not used to define an essence, order orsequence of a corresponding component but used merely to distinguish thecorresponding component from other component(s). It should be noted thatif it is described in the specification that one component is“connected,” “coupled” or “joined” to another component, a thirdcomponent may be “connected,” “coupled,” and “joined” between the firstand second components, although the first component may be directlyconnected, coupled or joined to the second component.

The present specification may is referred to an edge of a substrate asone of a side surface of the substrate, an edge surface of thesubstrate, both a side surface of the substrate and an outer part of twosurfaces.

FIG. 1 illustrates a sectional view of a touch device 100 according toone embodiment.

Referring to FIG. 1, the touch device 100 according to one embodimentmay be an integrated type touch device on a substrate 110. A touchsensor 120 in integrated type touch device 100 may be integrated on afirst surface 115 of the substrate 110, thereby making the devicelighter and thinner, reducing a manufacturing cost, improving visibilityfor a display and enhancing sensitivity for the touch device 100.

The touch sensor 120 and a decoration 130 around the touch sensor 120may be formed on the first surface 115 of the substrate 110 in the touchdevice 100.

The touch sensor 120 may include first electrodes positioned in a firstdirection such as a horizontal direction, and second electrodespositioned in a second direction such as a vertical direction.

An anti fingerprinted film may be attached on the substrate 110. Aflexible printed circuit board (FPCB, 125) in which a touch integratedcircuit and/or a controller is integrated, may be attached to one sideof the first surface 115 of the substrate 110.

An edge 135 of the substrate 110 on which the touch sensor 120 isformed, is strengthened by a chemical treatment with an etchant. Eitherlarge or small cracks are removed from the edge or the side surface 135of the substrate 110 with the touch sensor 120.

In detail, during manufacturing of the touch device 100 to be mentionedlater with reference to FIGS. 2 to 7, the edge or the substrate 110 maybe grinded by, for example, a chamfer, or chemically strengthened bybeing immersed in an etchant in a state that a protecting layer isformed on both surfaces so that only the edge thereof may be exposed.Therefore either large or small cracks may be removed from the edge orthe side surface 135 of the substrate 110.

When examined by an optical microscope, the edge 135 of the substrate110 may have a highly-smooth surface roughness or a high smoothness.When the edge 135 of the substrate 110 is examined by an atomic forcemicroscope, a surface roughness thereof may, for example, less than 1.2nm.

In order to manufacture the touch device 100 according to one embodimentas shown in FIG. 1, after a mother substrate may be divided into two ormore substrates (110) per cell unit and an edge 135 of each 110 of thesubstrates is chemically strengthened, the touch sensor 120 and thedecoration 130 may be formed on the substrate 110. Also, after two ormore touch sensors are formed on the mother substrate and the mothersubstrate is divided into two or more substrates per touch sensor unit,the edge thereof may be strengthened.

In order to improve productivity and cut down processing costs,described below is a method for manufacturing the touch device in whichafter two or more touch sensors are formed on the mother substrate andthe mother substrate is divided into two or more substrates per touchsensor unit. By this method the edge thereof may be strengthened.

FIG. 2 illustrates a flowchart of a method for manufacturing the touchdevice according to an embodiment. FIGS. 3 to 7 illustrate processes ofa method 200 for manufacturing the touch device according to anembodiment.

Referring to FIG. 2, the method 200 for manufacturing the touch devicemay comprise one or more of preparing a mother substrate at S210,forming two or more touch sensors on the prepared mother substrate atS220, forming a protective layer on the mother substrate at S230,dividing the mother substrate at S240, grinding an edge of the substrateat S250, strengthening the edge of the substrate S260 and removing theprotective layer at S270.

In more detail, referring to FIG. 3, in the preparing the mothersubstrate at S210, the mother substrate 310 may be, but not limited to,a strengthened glass substrate. For example, the strengthened glasssubstrate may be a glass substrate which is obtained by thermally orchemically treating a soda lime glass or an alkali-free glass in orderto enhance the hardness of the surface. Without separately performingthe preparation of the mother substrate at S210, the following step maybe performed by using the prepared mother substrate 310.

The process of forming the touch sensors can include forming two or moretouch sensors 120 on the first surface 115 of the mother substrate 310.In this step S220, the respective decorations 130 along with two or moretouch sensors 120 may be formed on the first surface 115 of the mothersubstrate 310. The touch sensors may comprise a first electrodepositioned in the first direction and the second electrode positioned inthe second direction respectively. For example, six touch sensors 120(e.g., by 3×2 configuration) may be formed at specific intervals on thefirst surface 115 of the mother substrate 310. The decoration 130 may beformed around the touch sensor 120 per one cell/touch sensor unit.

Referring to FIG. 4, in the process of forming the protective layer onthe mother substrate at S230, the protective layer 320 is formed, by aprinting process as an example, per one cell or touch sensor on thefirst surface 115 and the second surface 315 of the mother substrate 310on which two or more touch sensors are formed. In this step at S230, theprotective layer 320 may be formed by coating and then curing a paste ofa resin composition per one cell or touch sensor on the first surface115 and the second surface 315 opposite to the first surface 115 of themother substrate 310 through the printing process such as a screenprinting or a roll printing. The protective layer 320 may prevent damageof the substrate 110 and the touch sensor 120 from an etchant in thestrengthening the edge thereof at S260 because it is necessary toprotect the surface thereof before strengthening of the edge thereof.The protective layer 320 may be formed with an acid-resistant resincomposition because the edge 335 of the substrate 110 is treated by theetchant which includes an acidic aqueous solution as a main component inthe strengthening the edge thereof at S260.

The paste of the resin composition may be coated per one cell or touchsensor on the first surface 115 of the mother substrate 310, on whichthe above mentioned six touch sensors 115 (of 3×2) are formed, throughthe printing process such as the screen printing or the roll printing.The paste of the resin composition may be also coated per one cell ortouch sensor on the second surface 315 of the mother substrate 310through the printing process such as the screen printing or the rollprinting.

The paste of the resin composition coated at specific intervals on thefirst surface 115 and the second surface 315 of the mother substrate 310may be cured by, for example, being inserted into a firing furnace.

After the paste of the resin composition coated at specific intervals onthe first surface 115 of the mother substrate 310 may be coated and thencured by, for example, being inserted into a firing furnace, the pasteof the resin composition coated at specific intervals on the secondsurface 315 of the mother substrate 310 may be coated and then cured by,for example, being inserted into a firing furnace. Or vice versa.

In the process of forming the protective layer on the mother substrateat S230, the resin composition may be composed in order to be adapted tothe printing process such as the screen printing or the roll printing.

The resin composition to prevent damage of a surface of the substrate110 from an etchant when an edge 335 thereof is strengthened may includea resin mixture of 20-50% by weight which includes a phenol resin and aepoxy acrylate resin with a weight ratio of 10:90 to 90:10, and asolvent. Here, in one example, only the phenol resin and the epoxyacrylate resin may be included.

The solvent may be an organic solvent beneficial for dispersing theresin composition. The solvent may be 5 to 70% by weight when otheringredients are excluded from all of the resin composition. Further thesolvent may be an organic solvent of which the boiling point is highenough to be able to prevent what the paste of the resin composition isnot coated by being dried during the printing process. For example, thesolvent may be selected from a group consisting of DPGME (DipropyleneGlycol Methyl Ether), butyl carbitol), Terpineol, PGMEA (PropyleneGlycol Monomethyl Ether Acetate.

The phenol resin may be one of a novolac such as

or a resole such as

When the protective layer 320 is removed at S270, the phenol resin maybe suitable for stripping a surface. When the protective layer 320 isimmersed in the etchant 340 at S260, the phenol resin may be suitablefor preventing the penetration of the etchant or acid-resistance.Further epoxy acrylate resin may accelerate the curing and improve thesurface hardness when the paste of the resin composition is coated andcured on the first surface 115 of the mother substrate 310.

The appropriate weight ratio of the phenol resin and the epoxy acrylateresin may allow the resin composition to have characteristics adapted tostrip the surface, prevent the penetration of the etchant (oracid-resistance) and improve the surface hardness. In other words, theweight ratio of the phenol resin and the epoxy acrylate resin may bedetermined by considering the performance of stripping the surface whenthe protective layer 320 is removed, the characteristic of preventingthe penetration of the etchant (or acid-resistance) when immersed in theetchant 340, the characteristic of accelerating the curing or thesurface hardness when coated and cured, and other characteristic of thepaste. For example, the weight ratio of the phenol resin and the epoxyresin may be 10:90 to 90:10. If the phenol resin is less than 10% byweight, it is possible to decline the characteristic of preventing thepenetration of the etchant (or acid-resistance) when immersed in theetchant 340. If the phenol resin is more than 90% by weight, it ispossible to decline the performance of striping the surface when theprotective layer 320 is removed. If the epoxy acrylate resin is lessthan 10% by weight, it is possible to decline the surface roughness whencoated and cured. If the epoxy acrylate resin is more than 90% byweight, it is possible to decline the surface roughness when coated andcured.

In more detail, the weight ratio of the phenol resin and the epoxy resinmay be 40:60 to 80:20. When the weight ratio of the phenol resin is 40to 60 and the weight ratio of the epoxy acrylate resin is 20 to 60, itis confirmed that there are more improved features such as the improvedperformance of stripping the surface when the protective layer 320 isremoved, the improved characteristic of preventing the penetration ofthe etchant (or acid-resistance) when immersed in the etchant 340, theimproved characteristic of accelerating the curing or the surfacehardness when coated and cured, and other improved characteristics ofthe paste.

The weight percentage of a resin mixture consisting of or including thephenol resin and the epoxy acrylate resin in the resin composition maybe determined by considering the performance of striping the surface,the characteristic of preventing the penetration of the etchant (oracid-resistance), the characteristic of accelerating the curing or thesurface hardness, and other characteristic of the paste as mentionedabove. For example, the weight percentage of a resin mixture in all theresin composition as well as the weight ratio of the phenol resin andthe epoxy acrylate resin may be determined by considering theabove-mentioned characteristics. A viscosity of the resin compositionmay be 10,000˜60,000 mPa·s at room temperature. For example, if theviscosity of the resin composition is less than 10,000 mPa·s at roomtemperature, it is difficult to perform the printing process because thepaste of the resin composition is previously spread before the printingprocess. If the viscosity of the resin composition is more than 60,000mPa·s at room temperature, it is difficult to transfer the paste of theresin composition when coated by the printing process of the paste ofthe resin composition. For example, the screen is blocked in the screenprinting process and the roll is clunk/stuck in the roll printingprocess so that either the defect or the failure may occur in theprinting process.

Considering the performance of striping the surface, the characteristicof preventing the penetration of the etchant (or acid-resistance), thesurface hardness, and the viscosity of the resin composition asmentioned above, the resin mixture in all the resin composition may be20 to 50% by weight. If the resin mixture in the resin composition isless than 20% by weight, the surface hardness may be lowered and theviscosity of the resin composition may be less 10,000 mPa·s at roomtemperature. If the resin mixture in the resin composition is more than50% by weight, the viscosity of the resin composition may be more than60,000 mPa·s at room temperature and as a result the printing failuremay occur because of the difficulty of the transfer of the paste of theresin composition such as the blocking of the screen in the printingprocess and the clinging of the roll in the roll process.

The resin composition may mix other resin(s) into the above-mentionedresin composition and the solvent so that other properties may beobtained.

The resin composition according to the present invention may furtherinclude an elastomer to enhance/strengthen the surface elasticity andthe impact resistance. The elastromer may be, but not limited to, 0 to30% by weight among all the resin composition. The elastromer may beselected from a group consisting of an EPM (Ethylene propylene rubber),an EPDM (Ethylene propylene diene monomer rubber), a silicone rubber anda nitrile rubber, but is not limited thereto.

The resin composition according to the present invention may furtherinclude a photo initiator of less than 1% by weight. In order to givethe curing performance by exposure, the photo initiator may be selectedfrom a group consisting of dibenzoyl peroxide, dicumyl peroxide,tert-butyl peroxybenzoate and the like, but is not limited thereto.

The resin composition according to the present invention may furtherinclude a filler as well as the resin mixture and the solvent in orderto give the printing process characteristics and aid in securing thefilm thickness. For example, the filler may be selected from a groupconsisting of calcium carbonate, barium sulfate, titanium dioxide andsilica, but it is not limited thereto. The filler may be one of calciumcarbonate and barium sulfate in reference with the kind and theproportion of the resin mixture and the kind of the solvent. The fillermay be, not limited to, 10-50% by weight among all the resincomposition. An average particle size of the filler powder may be equalto or less than 2 μm, but it is not limited thereto. For example, if theaverage particle size of the filler powder is more than 2 μm, the fillermay be not dispersed uniformly in the resin composition or theperformance of the film may be lowered.

The resin composition according to the present invention may furtherinclude an additive of less than 1% by weight such as anti-foamingagents, leveling agents and anti-erosive/anti-abrasive agents generallyused in the composition in order to improve the performance of thedispersion and the membrane for the paste component, but is not limitedthereto.

Referring to FIG. 5, in the process of dividing the mother substrate atS240, the mother substrate 310 may be divided into two or moresubstrates 110 of the touch sensor unit by being mechanically cut orchemically treated.

In other words, in this step at S240, the mother substrate 310 may bedivided into two or more substrates of the touch sensor unit by beingmechanically cut with a cutter. In another example, in this step S240,the mother substrate 310 may be divided into two or more substrates(110) of the touch sensor unit by being chemically treated with theetchant.

In the process of grinding the edge of the substrate 110 at S250, theedge of the divided substrate 110 may be grinded by using, for example,a wheel grinder. Therefore the large cracks or the macro cracks may beremoved by grinding the edge of the mechanically cut substrate at S250.In detail, the chamfer 330 of the edge of the mechanically cut substrate110 may be sequentially performed by using the wheel grinder so that thelarge cracks may be removed from the substrates (110) at S250.

However, the process of grinding the edge of the substrate at S250 maybe omitted and the following step may be performed when the cracks ofthe edge of the divided substrate is sufficiently removed by beingmechanically cut at S250 and/or being chemically treated at S260.

Referring to FIG. 6, in the process of strengthening the edge of thesubstrate 110 at S260, the edge 335 of the divided substrate 110 of thetouch sensor unit may be chemically strengthened. In this step S260, thedivided substrate 110 of the touch sensor unit may be immersed in theetchant 340 so as remove the small cracks or the microcracks. In thisstep S260, a predetermined portion 345 (i.e., the etched portion) of theedge 335 of the substrate 110 is etched to be strengthened so that theedge 115 of the substrate may be completed.

For example, the divided substrate 110 may be immersed in the etchantincluding an acidic aqueous solution such as a hydrofluoric acidsolution with hydrofluoric acid of about 10% as a main component byusing a chemical healing method. As for the etchant, it is possible tosuitably use a mixed acid containing at least one of hydrofluoric acid,sulfuric acid, nitric acid, hydrochloric acid, and hydrofluorosilicicacid. In this step S260, the etching process is not limited to theprocess of simply immersing the substrate into the etchant or theetching solution, but instead it is possible to employ, for example,spray etching in which the etchant or the etching solution is sprayed.

Referring to FIG. 7, the protective layer 320 may be removed from thesubstrate 110 so that the touch device 100 may be completed.

In this step S270, the substrate 110 on which the protective layer 320is formed may be either immersed in a stripper or sprayed with thestripper so that the protective layer 320 may be removed.

The stripper or the stripping solution for stripping the protectivelayer 320 may be an organic solvent mixture or an aqueous alkalinesolution depending on the kind and the mixing ratio of the resincomposition, and the mixing combination used for forming the protectivelayer 320, but is not limited thereto. For example the stripper may bethe aqueous alkaline solution such as an aqueous potassium hydroxidesolution or an aqueous amine-based solution for recycling. The substrate110 may be sufficiently washed by a washing liquid in order to preventcorrosion of the pattern of touch sensor.

After the substrate 110 is sufficiently washed by the washing liquid,the decoration 130 may be reinforced around the touch sensor 120 byfurther printing processes. The anti fingerprinted film may be attachedon the substrate 110 for protecting the touch sensor 120 and theflexible printed circuit board (FPCB, 125) in which a touch integratedcircuit and/or a controller is integrated, may be attached to one sideof the first surface 115 of the substrate 110 so that the touch device100 may be completed.

In the above-mentioned embodiment(s), there may form the proactive layer320 with the resin composition on the touch sensor before the process ofstrengthening the edge of the substrate on which the touch sensor isformed. This can effectively prevent the damage of the surface of thesubstrate 110 due to the etchant in the process of strengthening theedge of the substrate.

In the above-mentioned embodiment(s), the paste of the resin compositioncan be coated on the substrate by the printing process so as to simplifythe coating process and relatively easily perform the stripping processafter strengthening the substrate.

Although various embodiments have been described up to now withreference to the accompanying drawings, the present invention is notlimited thereto. For example, the type of the additives of the resincomposition, the etchant, and the stripper may be selected asappropriate depending on the material(s) of the substrate, the variousprocesses and the like.

Although preferred embodiments of the present invention have beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims. Therefore, the embodimentsdisclosed in the present invention are intended to illustrate the scopeof the technical idea of the present invention, and the scope of thepresent invention is not limited by the embodiment. The scope of thepresent invention shall be construed on the basis of the accompanyingclaims in such a manner that all of the technical ideas included withinthe scope equivalent to the claims belong to the present invention.

What is claimed is:
 1. A method for manufacturing a touch device, themethod comprising: forming a protective layer per touch sensor on firstand second surfaces of a mother substrate on which two or more touchsensors are formed; dividing the mother substrate into two or moresubstrates of a touch sensor unit by mechanically cutting or chemicallytreating the mother substrate; chemically strengthening an edge of eachof the divided substrates; and removing the protective layer from atleast one divided substrate, wherein in the forming of the protectivelayer, the protective layer is formed by coating a paste of a resincomposition comprising a resin mixture of 20-50% by weight whichincludes a phenol resin and an epoxy acrylate resin with a weight ratioof 10:90 to 90:10, and a solvent of 5 to 70% by weight on the first andsecond surfaces of the mother substrate, wherein the resin compositionfurther comprises a filler of 10-50% by weight selected from a groupconsisting of calcium carbonate, barium sulfate, titanium dioxide andsilica, and wherein the solvent is selected from a group consisting ofdiprophylene glycol methyl ether, butyl carbitol, and terpineol.
 2. Themethod as claimed in claim 1, wherein the resin composition furthercomprises an elastomer and a photo initiator of 1 to 50% by weight. 3.The method as claimed in claim 1, wherein a viscosity of the resincomposition is 10,000˜60,000 mPa·s at room temperature.
 4. The method asclaimed in claim 2, wherein the elastomer is selected from a groupconsisting of an EPM (Ethylene propylene rubber), an EPDM (Ethylenepropylene diene monomer rubber), a silicone rubber and a nitrile rubber.5. The method as claimed in claim 1, wherein the filler has an averageparticle size of approximately 2 μm.